But at this point in time... and probably any point in time now... the characters made for Post-SGW that Archie has control of are essentially useless to them. I highly doubt Archie would make their own comic with the characters.
Then why prevent them from channeling over?
To be honest, I don't know the reason either. All that we do know, though, is that IDW cannot continue the Archie Reboot continuity or reprint any of the issues despite the license being shifted to them. It's possible any original and exclusive content formally associated with them was also prevented for the exact same reasons.
It's especially baffling given that, as you said, the material is practically useless without SEGA's license. But if Archie has somehow retained partial ownership of them and cannot do anything with them without SEGA, then they're pretty much in limbo at the moment.
But if, say, SEGA decides to purchase them to transfer over to IDW or they're waiting for the permits to expire, we could see something come about. But that's only guesswork. We don't really know the direct cause of all this is.